Method and apparatus for transmitting data and control information on multiple uplink carrier frequencies

ABSTRACT

A method and an apparatus for wireless transmission using multiple uplink carriers are disclosed. A wireless transmit/receive unit (WTRU) may transmit via a primary uplink carrier data, pilot and control channels for uplink transmissions on both uplink carriers, and transmit a data channel and a pilot channel via a secondary uplink carrier. Alternatively, the WTRU may transmit via a primary uplink carrier data, pilot, and control channels for uplink transmission on the primary uplink carrier, and transmit via a secondary uplink carrier data, pilot, and control channels for uplink transmissions on the secondary uplink carrier. Each uplink carrier may be associated with at least one specific downlink carrier such that the WTRU applies control information received on a downlink carrier to uplink transmissions on an uplink carrier associated with the downlink carrier on which the WTRU receives the control information.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.12/610,294 filed Oct. 31, 2009; which claims the benefit of U.S.provisional application Nos. 61/109,978 filed Oct. 31, 2008, 61/117,494filed Nov. 24, 2008, 61/117,851 filed Nov. 25, 2008, 61/141,638 filedDec. 30, 2008, and 61/148,690 filed Jan. 30, 2009, which areincorporated by reference as if fully set forth herein.

FIELD OF INVENTION

This application is related to wireless communications.

BACKGROUND

A number of improvements have been introduced in universal mobiletelecommunication systems (UMTS) wireless communications systems toincrease the data rates available to end users. Following theintroduction of high speed downlink packet access (HSDPA) for thedownlink in Release 5 of the third generation partnership project(3GPP), high speed uplink packet access (HSUPA) was introduced as partof Release 6 of the 3GPP to improved uplink performance. The HSUPA useshybrid automatic repeat request (HARQ) combined with short transmissiontime intervals (TTI) and fast scheduling to improve the uplinkthroughput and peak data rate over the new enhanced dedicated channel(E-DCH).

As wideband code division multiple access (WCDMA) is aninterference-limited system, tight control of the uplink transmissionpower of every wireless transmit/receive unit (WTRU) is important. Thisis achieved via a combination of power control and grant mechanism. Agrant for E-DCH transmission is a maximal power ratio that a WTRU mayuse to transmit on the E-DCH. The grant is translated directly to atransport block size. In this context, the grant can be interpreted as aright to create interference on the uplink. In HSUPA, the networksignals a grant to each WTRU separately. There are two types of grantssignaled by the network: an absolute grant and a relative grant. Theabsolute grant is transmitted over an E-DCH absolute grant channel(E-AGCH) by the serving E-DCH cell and carries an index to a granttable. The relative grant may be transmitted by any cell in the E-DCHactive set over an E-DCH relative grant channel (E-RGCH). The WTRUmaintains a serving grant that the WTRU uses to determine how much datamay be transmitted during a given TTI. This serving grant is updatedevery time a new grant command is received either over the E-AGCH or theE-RGCH.

In addition to the grant mechanism, HSUPA also takes advantage of themacro-diversity by allowing non-serving E-DCH cells to transmit HARQpositive acknowledgement (ACK) to WTRUs over an E-DCH HARQ indicatorchannel (E-HICH) whenever the transmitted data is correctly decoded. Theserving E-DCH cell (and the non-serving E-DCH cells in the same radiolink set (RLS)) transmits an ACK or a negative acknowledgement (NACK)over the E-HICH for each received HARQ transmission.

The downlink control channel specific to HSUPA comprises the E-AGCH, theE-RGCH, and the E-HICH. For proper operation of the system, a powercontrol loop using a fractional dedicated physical channel (F-DPCH) onthe downlink and a dedicated physical control channel (DPCCH) on theuplink is established.

In order to meet the growing needs for providing continuous and fasteraccess to a data network, a multi-carrier system that is capable ofusing multiple carriers for the transmission of data has been proposed.The use of multiple carriers is expanding in both cellular andnon-cellular wireless systems. A multi-carrier system may increase thebandwidth available in a wireless communication system according to amultiple of how many carriers are made available. For instance, as partof the evolution of the technology, a new feature called dual-cell HSDPA(DC-HSDPA) has been introduced in the Release 8 specifications of the3GPP. With DC-HSDPA, a Node-B communicates to WTRUs over two distinctdownlink carriers simultaneously. It not only doubles the bandwidth andthe peak data rate available to WTRUs, but also has a potential toincrease the network efficiency by means of fast scheduling and fastchannel feedback over two carriers.

DC-HSDPA significantly increases the throughput and efficiency of thedownlink in the wireless communications systems. The introduction ofDC-HSDPA further augments the asymmetry between the uplink and downlinkin terms of throughput and peak data rates. However, no proposals havebeen made for the uplink. Therefore, it would be desirable to provide amethod for exploiting the multiple uplink carriers for increasing thepeak data rates and transmission efficiencies in uplink transmissions.

SUMMARY OF THE INVENTION

A method and an apparatus for wireless transmission using multipleuplink carriers are disclosed. A WTRU may transmit via a primary uplinkcarrier a data channel, a pilot channel, and a control channel foruplink transmission on the primary uplink carrier and optionally acontrol channel for providing uplink feedback information related todownlink transmission, and transmit a data channel and a pilot channelvia a secondary uplink carrier. Alternatively, the WTRU may transmit viaa primary uplink carrier a data channel, a pilot channel, a controlchannel for uplink transmission on the primary uplink carrier andoptionally a control channel for providing uplink feedback informationrelated to downlink transmission, and transmit via a secondary uplinkcarrier a data channel, a pilot channel, and a control channel foruplink transmissions on the secondary uplink carrier.

Each uplink carrier may be associated with at least one specificdownlink carrier such that the WTRU applies control information receivedon a downlink carrier to uplink transmissions on an uplink carrierassociated with the downlink carrier on which the WTRU receives thecontrol information. At least one radio network temporary identity(E-RNTI) may be configured per uplink carrier and the WTRU may apply areceived absolute grant to uplink data transmissions (e.g., E-DCH) on anassociated uplink carrier. At least one downlink control channelconveying uplink grant information (e.g., E-AGCH) may be associated toeach uplink carrier and the WTRU may apply a received absolute grant touplink transmission on an uplink carrier associated with a downlinkcontrol channel carrying the uplink grant information on which theabsolute grant is received. One set of downlink control channelscarrying relative uplink grant information (e.g., E-RGCH) and HARQfeedback information (e.g., E-HICH) may be associated to each uplinkcarrier, and the WTRU may apply received relative grant and HARQfeedback to uplink transmissions on an associated uplink carrier.

The WTRU may receive multiple transmit power control (TPC) commands, andadjust transmit power on an uplink carrier based on a corresponding TPCcommand. A TPC command for an uplink carrier may be received over adownlink carrier associated to that uplink carrier.

BRIEF DESCRIPTION OF THE DRAWINGS

A more detailed understanding may be had from the following description,given by way of example in conjunction with the accompanying drawingswherein:

FIG. 1 shows an example wireless communication system;

FIG. 2 is a functional block diagram of a WTRU and the Node-B of thewireless communication system of FIG. 1;

FIG. 3 shows an example that a WTRU transmits two uplink carriers to theUTRAN in accordance with one embodiment;

FIG. 4 shows an example that a WTRU transmits two uplink carriers to theUTRAN in accordance with another embodiment;

FIG. 5 is a functional block diagram wherein two uplink carriers arecontrolled by transmit power control (TPC) commands transmitted to aWTRU on two downlink carriers;

FIGS. 6 and 7 are functional block diagrams wherein two uplink carriersare controlled by transmit power control (TPC) commands transmitted to aWTRU on a single downlink carrier;

FIG. 8 shows an example F-DPCH slot format in accordance with oneembodiment;

FIG. 9 is a functional block diagrams wherein transmit power control(TPC) commands are sent in the uplink in a multiple uplink carrierenvironment;

FIG. 10 is a flow diagram of an example process for E-TFC selection andMAC-e or MAC-i PDU generation while utilizing two uplink carriers; and

FIG. 11 shows scheduling information format in accordance with oneembodiment.

DETAILED DESCRIPTION

When referred to hereafter, the terminology “WTRU” includes but is notlimited to a user equipment (UE), a mobile station, a fixed or mobilesubscriber unit, a pager, a cellular telephone, a personal digitalassistant (PDA), a computer, a machine-to-machine (M2M) device, asensor, or any other type of device capable of operating in a wirelessenvironment. When referred to hereafter, the terminology “Node-B”includes but is not limited to a base station, a site controller, anaccess point (AP), or any other type of interfacing device capable ofoperating in a wireless environment.

The network may assign at least one downlink and/or at least one uplinkcarrier as an anchor downlink carrier and an anchor uplink carrier,respectively. For example, the anchor carrier may be defined as thecarrier for carrying a specific set of control information fordownlink/uplink transmissions. The anchor carrier may not be dynamicallyactivated and deactivated. The uplink anchor carrier may be associatedwith the downlink anchor carrier. Any carrier that is not assigned as ananchor carrier is a supplementary carrier. Alternatively, the networkmay not assign an anchor carrier and no priority, preference, or defaultstatus may be given to any downlink or uplink carriers. Formulti-carrier operation more than one supplementary carriers orsupplementary carriers may exist. Hereinafter, the terminologies “anchoruplink/downlink carrier” and “primary uplink/downlink carrier” will beused interchangeably and the terminologies “secondary uplink/downlinkcarrier” and “supplementary uplink/downlink carrier” will be usedinterchangeably.

Embodiments for utilizing multiple uplink carriers in transmission ofdata and control information in HSPA systems, including various channelstructures for the uplink carriers to covey user data and controlinformation are disclosed. Even though embodiments are described interms of dual uplink carrier, it should be understood that theembodiments described herein are applicable to multiple uplink carriersas well. Even though the embodiments are disclosed with reference tocontrol channels and data channels associated to wideband code divisionmultiple access (WCDMA), it should be noted that the embodiments areapplicable to any wireless communication technologies that are currentlyexisting or will be developed in the future, such as long term evolution(LTE) and LTE-Advanced. It should also be noted that the embodimentsdescribed herein may be applicable in any order or combinations.

FIG. 1 shows an example wireless communication system 100 including aplurality of WTRUs 110, a Node-B 120, a controlling radio networkcontroller (CRNC) 130, a serving radio network controller (SRNC) 140,and a core network 150. The Node-B 120 and the CRNC 130 may collectivelybe referred to as the UTRAN.

As shown in FIG. 1, the WTRUs 110 are in communication with the Node-B120, which is in communication with the CRNC 130 and the SRNC 140.Although three WTRUs 110, one Node-B 120, one CRNC 130, and one SRNC 140are shown in FIG. 1, it should be noted that any combination of wirelessand wired devices may be included in the wireless communication system100.

FIG. 2 is a functional block diagram of a WTRU 110 and the Node-B 120 ofthe wireless communication system 100 of FIG. 1. As shown in FIG. 1, theWTRU 110 is in communication with the Node-B 120 and both are configuredto perform a method of performing uplink transmissions with multipleuplink carriers. The WTRU 110 includes a processor 115, a receiver 116,a transmitter 117, a memory 118, an antenna 119, and other components(not shown) that may be found in a typical WTRU. The memory 118 isprovided to store software including operating system, application, etc.The processor 115 is provided to perform, alone or in association withthe software, a method of performing uplink transmissions with multipleuplink carriers. The receiver 116 and the transmitter 117 are incommunication with the processor 115. The receiver 116 and/or thetransmitter 117 may be capable of receiving and/or transmitting overmultiple carriers. Alternatively, multiple receivers or transmitters maybe included in the WTRU 110. The antenna 119 is in communication withboth the receiver 116 and the transmitter 117 to facilitate thetransmission and reception of wireless data.

The Node-B 120 includes a processor 125, a receiver 126, a transmitter127, a memory 128, an antenna 129, and other components (not shown) thatmay be found in a typical base station. The processor 125 is provided toperform, alone or in association with the software, a method ofperforming uplink transmissions with multiple uplink carriers. Thereceiver 126 and the transmitter 127 are in communication with theprocessor 125. The receiver 126 and/or the transmitter 127 may becapable of receiving and/or transmitting over multiple carriers.Alternatively, multiple receivers or transmitters may be included in theNode B 120. The antenna 129 is in communication with both the receiver126 and the transmitter 127 to facilitate the transmission and receptionof wireless data.

In accordance with one embodiment, a secondary uplink carrier carriestraffic data with minimal or no control information. FIG. 3 shows anexample that a WTRU transmits two uplink carriers to the UTRAN. The WTRUmay transmit a data channel, (e.g., E-DCH dedicated physical datachannel (E-DPDCH)), and pilot and other control channels, (e.g., DPCCH,E-DCH dedicated physical control channel (E-DPCCH), and/or HS-DSCHdedicated physical control channel (HS-DPCCH)), on the anchor uplinkcarrier, and transmit a data channel (e.g., E-DPDCH) and a pilot channelon the supplementary uplink carrier.

The anchor uplink carrier may carry all or most of the uplink controlsignaling that is sent to the UTRAN including at least one of, but notlimited to: (1) feedback for downlink channels (such as HS-DPDCH)including channel quality information (CQI), precoding controlindication (PCI), ACK/NACK HARQ information; (2) uplink radio linkcontrol information, (e.g., uplink DPCCH), including uplink pilotsymbols, feedback information (FBI), and transmission power control(TPC) commands; or (3) E-DCH control information, (e.g., E-DPCCH),including retransmission sequence number (RSN) used for HARQ processing,E-DCH transport format combination index (E-TFCI) information indicatingthe size of the transmitted transport blocks, and a happy bit.

The data channel, (e.g., E-DPDCH), may convey user traffic on the anchoruplink carrier as illustrated in FIG. 3.

The supplementary uplink carrier may carry a user data channel (e.g.,E-DPDCH) and a pilot channel. The pilot channel may be the conventionaluplink DPCCH that carries pilot symbols as well as transmit powercontrol (TPC) commands. The TPC commands may be used to control asecondary power control loop between the WTRU and the UTRAN that governsthe downlink power for a secondary downlink carrier. Alternatively, thepilot channel may have a new slot format of the uplink DPCCH thatincludes pilot symbols. For example, all ten (10) bits of theconventional uplink DPCCH may be used to carry the pilot sequence.Alternatively, the pilot channel may be a new uplink control channelthat carries pilot symbols that are used by the UTRAN to improve thereception of data on the secondary uplink carrier.

The E-DCH control information for both data sent on the anchor uplinkcarrier and data sent on the supplementary uplink carrier may be sent onthe anchor uplink carrier. This E-DCH control information may beconveyed by defining a new slot format for E-DPCCH that includes controlinformation for both uplink carriers or by transmitting two independentE-DPCCH channels on the anchor uplink carrier (one for the anchor uplinkcarrier and the other for the supplementary uplink carrier).

In accordance with alternate embodiment, the secondary uplink carriermay also carry the E-DCH control information that is associated with thetransmission of the secondary uplink carrier, as shown in FIG. 4. TheE-DCH control information that is transmitted on the anchor uplinkcarrier is related to the data transmission on the anchor uplinkcarrier. A separate E-DPCCH may be sent on the secondary uplink carrierfor transmitting the E-DCH control information in addition to the dataand pilot channels (in a similar manner to single carrier operation).Alternatively, a new uplink control channel that includes both the pilotand E-DCH control information may be defined. The new uplink controlchannel may include uplink pilot symbols, FBI, TPC, RSN used for HARQprocessing, E-TFCI information indicating the size of transmittedtransport blocks, and/or happy bit. Alternatively, the new uplinkcontrol channel may include the pilot symbols, the RSN, and/or theE-TFCI information.

In case where the E-DPCCH is sent on both anchor and supplementaryuplink carriers, the happy bit may be set on both uplink carriers asfollows. The happy bit on each uplink carrier may be set according tothe respective power headroom conditions and individual grants of eachuplink carrier. Power headroom may be defined as the amount of power orratio available for the transmission of uplink data. Alternatively, thepower headroom may be the amount of power or ratio available over areference uplink channel for the transmission of other uplink data andcontrol channels. This means that the happy bit may be set to “happy” onone uplink carrier while the happy bit is set to “unhappy” one thesecond uplink carrier, if for instance there is enough power headroom totransmit at a higher data rate on the second uplink carrier, or if thegrant on the second uplink carrier is lower.

Alternatively, the happy bit on one uplink carrier (e.g., the anchoruplink carrier) may be set according to the combined conditions (grantand power headroom) of both uplink carriers. In this case, the happy bitmay be set to “unhappy” (1) if the WTRU is transmitting as muchscheduled data as allowed by the current serving grants on both uplinkcarriers in E-TFC selection for both uplink carriers, (2) if the WTRUhas enough power available to transmit at higher data rate on any or allof the uplink carriers; or (3) based on the same power offset(s) as theone selected in E-TFC selection (on both uplink carriers) to transmitdata in the same TTI as the happy bit, if total E-DCH buffer status(TEBS) would require more than Happy_Bit_Delay_Condition ms to betransmitted with the current serving grants, taking into account theratio of active processes to the total number of processes on eachcarrier.

If the happy bit on one uplink carrier is set according to the combinedconditions of both uplink carriers, the happy bit on the second uplinkcarrier may be interpreted in one or a combination of the following:

(1) The happy bit may be set to “happy” if the power headroom on thesecond uplink carrier is larger than the power headroom on the firstuplink carrier, and “unhappy” otherwise. This information helps thenetwork determine which carrier the grant may be increased on; or

(2) Alternatively, the happy bit on the second uplink carrier may be setas per the conventional rules for happy bit determination consideringthe grant and power headroom conditions on the second uplink carrieronly (or on the first uplink carrier only).

All uplink carriers may have the same channel structure, including adata channel (e.g., E-DPDCH) and control channels (e.g., DPCCH, E-DPCCHor HS-DPCCH). Each uplink carrier may be paired with an associateddownlink carrier. This may be advantageous for the case the carriers arelocated in different frequency bands and radio conditions may differsignificantly between the carriers.

The number of uplink carriers and the number of downlink carriers may bethe same. In this case, each uplink carrier may be paired with adownlink carrier. In an example case of two downlink carriers and twouplink carriers, downlink carrier 1 may carry all control informationassociated with uplink carrier 1, including uplink schedulinginformation (e.g., E-AGCH, E-RGCH), HARQ feedback (e.g., E-HICH), powercontrol commands (e.g., via F-DPCH), or the like. Similarly, downlinkcarrier 2 may carry all control information associated with uplinkcarrier 2.

Uplink carrier 1 may carry all control information associated withdownlink carrier 1, including downlink channel quality (e.g., CQI onHS-DPCCH), HARQ feedback (e.g., ACK/NACK on HS-DPCCH), power controlcommands (e.g., uplink DPCCH), or the like. Similarly, uplink carrier 2may carry all control information associated with downlink carrier 2.

Alternatively, the number of downlink carriers may be more than thenumber of uplink carriers. In this case, it is allowed to receive moredownlink carriers than are used for uplink transmissions. For example,in case that a WTRU is configured to simultaneously receive on four (4)downlink carriers while transmitting on two (2) uplink carriers, uplinkcarrier 1 may be matched to downlink carrier 1 (anchor) and downlinkcarrier 2 (supplementary), and uplink carrier 1 may carry any or all ofthe control information related to downlink carrier 1 and downlinkcarrier 2 including downlink channel quality (e.g., CQI on HS-DPCCH),HARQ feedback (e.g., ACK/NACK on HS-DPCCH), power control commands(e.g., uplink DPCCH) or the like. Uplink carrier 2 may be matched todownlink carrier 3 (anchor) and downlink carrier 4 (supplementary), anduplink carrier 2 may carry any or all of the control information relatedto downlink carrier 3 and downlink carrier 4 including downlink channelquality (e.g., CQI on HS-DPCCH), HARQ feedback (e.g., ACK/NACK onHS-DPCCH), power control commands (e.g., uplink DPCCH), or the like.

With multiple carriers on the uplink, the active set of the WTRU may bemodified. A WTRU may maintain two active sets corresponding to eachuplink carrier independently. The WTRU may have an active set includingthe E-DCH radio links on the anchor uplink carrier and another activeset including E-DCH radio link on the supplementary uplink carrier. Thiswould allow the network to configure some single cell Node-Bs and somedual cell Node-Bs in the same E-DCH active set.

Alternatively, the WTRU may maintain one active set, wherein each entryin the active set includes the radio links associated to both the anchorand supplementary uplink carriers. In this embodiment, the network maynot configure the WTRU with single E-DCH configuration on some sectorsand with dual E-DCH in some other sectors.

Alternatively, the non-serving cells of the E-DCH active set maycomprise one carrier radio link and the serving cell may comprise tworadio links (one corresponding to the anchor carrier and one to thesupplementary carrier).

Embodiments for providing the necessary signaling to operate HSUPA overmultiple carriers are explained hereafter.

In accordance with one embodiment, each uplink carrier may be associatedwith a specific downlink carrier for the control signaling. Theassociation may be signaled by the network via radio resource control(RRC) signaling or may be implicitly known based on predefined set ofrules. For example, in case that two uplink carriers and two downlinkcarriers are utilized, and uplink carrier A and downlink carrier A, anduplink carrier B and downlink carrier B are associated, a WTRU may applythe E-AGCH, E-RGCH and E-HICH commands received on downlink carrier A tothe serving grant and HARQ processes associated to uplink carrier A.Likewise, the WTRU applies the E-AGCH, E-RGCH and E-HICH commandsreceived on downlink carrier B to the serving grant and HARQ processesassociated to uplink carrier B.

In accordance with another embodiment, the downlink carrier over whichthe E-AGCH, E-RGCH or E-HICH command is transmitted may not be directlylinked to the uplink carrier to which these commands apply. The grantsmay be transmitted only on the anchor downlink carrier (or alternativelyon any of the downlink carriers) and may be applied to any of the uplinkcarriers.

Embodiments for transmitting the absolute grant for multiple uplinkcarriers are explained hereafter.

In accordance with one embodiment, the network may configure one set ofE-DCH radio network temporary identity (E-RNTI) for each uplink carrierat the WTRU. Each set of E-RNTI (i.e., primary E-RNTI and secondaryE-RNTI) is associated to a given uplink carrier. Optionally, only theprimary E-RNTI may be configured for each uplink carrier. The WTRUmonitors the E-AGCH for all the E-RNTIs configured, and when one of theE-RNTI configured is detected, the WTRU applies the command carried overthe E-AGCH to the uplink carrier associated to the decoded E-RNTI. Theassociation of E-RNTI to uplink carrier is valid regardless of thedownlink carrier over which the E-AGCH is transmitted.

Alternatively, the network may configure at least one E-AGCH (i.e.,E-AGCH channelization code) associated to each uplink carrier. The WTRUmonitors all E-AGCH (i.e., all E-AGCH channelization codes configured).When the WTRU detects its E-RNTI (primary or secondary) on theconfigured E-AGCHs, the WTRU applies the corresponding command to theuplink carrier associated to the E-AGCH channelization code over whichthe command was transmitted.

Alternatively, the WTRU may apply the received E-AGCH command to one ofthe uplink carrier based on the timing. For example, the uplink carrierindex to which the command applies to may be a function of the E-AGCHsubframe number and the connection frame number (CFN) (or system framenumber (SFN)) of the received E-AGCH. In addition, at a given sub-frame,the time offset between the sub-frame when the E-AGCH command istransmitted and the sub-frame of the corresponding E-DCH transmissionmay be different depending on the uplink carrier. For instance, the timeoffset may be approximately 5 sub-frames for uplink carrier #1 but one(1) less sub-frame (i.e., .about.4 sub-frames) for uplink carrier #2.

The time offsets may be swapped every HARQ cycle (8 TTIs for 2 ms TTIand 4 TTIs for 10 ms TTI) to allow absolute grant commands to addressany HARQ process for both carriers.

Alternatively, in the special case of two uplink carrier, the absolutegrant scope bit carried on the E-AGCH may be re-interpreted to indicatethe uplink carrier to which the accompanying absolute grant commandapplies to.

Alternatively, the physical layer format of the E-AGCH may be modifiedto support two or more uplink absolute grant commands. This may beachieved by reducing the absolute grant granularity (from 5 bits tolower values), by re-interpreting the absolute grant scope bit to carryother information, by changing the channel coding scheme to support moreinformation, or by sharing the absolute grant scope bit among all uplinkcarriers, or in any combination thereof.

Alternatively, the E-AGCH format may be modified such that an additionalfield is added to the absolute grant message to explicitly indicate theuplink carrier to which this absolute grant command is applicable to.Depending on the number of carriers in the uplink this field may be 1bit for dual cell operation or two bits to support up to 4 carriers.

Alternatively, the WTRU may be provided with a single grant value thatapplies to the combined transmissions on both carriers. The signaledgrant (power ratio) may be translated into a number of bits (or a datarate) and the WTRU may not be allowed to transmit a higher total numberof bits (or at a total higher data rate) over both carriers.Alternatively, the linear sum of the E-DPDCH/DPCCH power ratios of bothcarriers may not be allowed to exceed the signaled grant.

The restriction signaled by this single grant may be combined with otherrestrictions to determine the proper sharing between the two carriers.For instance, the network may signal semi-statically or dynamically amaximum grant on either (or both) uplink carrier for interferencecontrol purposes. Conventional mechanisms to control the grant onindividual carriers may be used in conjunction with the shared grant. Inthis case the shared grant may be identified with a distinct E-RNTIvalue.

Embodiments for transmitting the relative grant and HARQ indication formultiple uplink carriers are explained hereafter.

In accordance with one embodiment, one set of E-RGCH and E-HICH (foreach radio link) may be configured for each uplink carrier. A differentset of E-RGCH and E-HICH may share the same channelization code withdifferent signatures, or may use a different channelization codealtogether. Each set is associated to a specific uplink carrier. Thisassociation may be indicated via explicit signaling or may be implicitlyknown by pre-defined rules. The E-RGCH and E-HICH are then transmittedover a pre-defined downlink carrier, independently of the uplink carrierassociation. For example, all sets of E-RGCH and E-HICH may betransmitted over the serving HS-DSCH cell (the anchor downlink carrier).A certain E-RGCH may be associated to both uplink carriers, and in thiscase, an UP (or DOWN) command would raise (or lower) the grant on bothuplink carriers simultaneously.

Alternatively, each uplink carrier may be associated to one downlinkcarrier. The network configures one set of E-RGCH and E-HICH (for eachradio link) per uplink carrier, which is transmitted over the associateddownlink carrier. The WTRU monitors the E-RGCH and E-HICH over eachdownlink carrier and applies the received command to the associateduplink carrier. For instance, if uplink carrier A is associated todownlink carrier A, then the E-HICH and E-RGCH commands received overdownlink carrier A are applied to the uplink carrier A.

The WTRU may receive E-RGCH and E-HICH from non-serving Node-Bs for eachuplink carrier. Since the non-serving Node-Bs may not be capable of dualuplink operation, separate E-DCH active sets may be defined for eachuplink carrier. A WTRU may receive non-serving E-RGCH or E-HICH from anon-serving Node-B for at least one of the uplink carriers. For the samereason, separate active sets may be defined for each uplink carriers forpower control purposes. In this case, the WTRU may receive TPC commands(on the DPDCH or F-DPCH) from a Node-B for one of the uplink carriers.

If parallel control for the uplink carriers is not allowed, the WTRU maynot have to maintain a separate active set for each carrier. One activeset may be defined and the downlink control signaling may be monitoredfrom the active set of the downlink anchor carrier.

Due to the overhead associated to the supplementary uplink carrier, itmay be desirable to constrain the use of the supplementary carrier orthe use of two uplink carriers at a time to WTRUs in burst periods. Inthis context, it may be efficient to allocate the uplink resources(i.e., only the supplementary uplink carrier or alternatively bothsupplementary and anchor uplink carriers) to a single WTRU at a time,(i.e., one WTRU at a given time is allowed to transmit on both carriersor the supplementary carrier, and all other WTRUs are allowed totransmit only on the anchor carrier).

In accordance with one embodiment, a WTRU may be scheduled or configuredto use its grant on the supplementary uplink carrier or on both uplinkcarriers for a pre-defined or configured period of time. The WTRU may betransmitting on only one uplink carrier, (either the anchor orsupplementary uplink carrier), and the scheduler schedules the WTRU onboth uplink carriers. This allows the network to minimize the signalingwhen switching the resource among WTRUs.

In an initial state, a WTRU is transmitting an E-DCH only on the anchoruplink carrier or only on the supplementary uplink carrier (only oneuplink carrier may be activated and the other uplink carrier may or maynot be activated). When the WTRU has large amount of data to transmit,the network may decide to temporarily provide a grant on the uplinkcarrier that is not currently being used. In order to signal or triggerthe WTRU to initiate transmission on both uplink carriers, one or acombination of the following conditions may be used: (1) The WTRUreceives a non-zero grant associated to the uplink carrier on which itis not currently transmitting data (i.e., E-DCH) on; (2) The WTRU has anon-zero grant and at least one active HARQ process on the anchor uplinkcarrier or on the supplementary uplink carrier, and receives a non-zerogrant for the uplink carrier on which it is not currently transmitting;or (3) The WTRU has a non-zero grant and all HARQ processes activated onthe anchor uplink carrier or the supplementary uplink carrier, andreceives a non-zero grant for the uplink carrier on which it is notcurrently transmitting.

The WTRU may be signaled to initiate transmission on the other carrierusing one or a combination of the following ways. The WTRU may beassigned an E-RNTI (referred to as “dual cell E-RNTI” hereafter) whichis used to indicate to the WTRU to start transmission on both carriers.The WTRU may also have a single cell E-RNTI or two separate E-RNTIs forsingle cell use (one for the anchor and one for the supplementary). IfE-AGCH is masked with the dual cell E-RNTI, the WTRU initiatestransmission on both uplink carriers at the HARQ process correspondingto the given E-AGCH. The grant signaled on the E-AGCH with the dual cellE-RNTI may be used on the new uplink carrier to be used, and the WTRUmay continues with the existing serving grant on the carrier in whichthe WTRU was already transmitting. Alternatively, the grant signaled onthe E-AGCH with the dual cell E-RNTI may be used for both uplinkcarriers. Alternatively, the grant signaled on the E-AGCH with the dualcell E-RNTI may be split in half between both uplink carriers.

Alternatively, the absolute grant table may be extended to allowsignaling of higher value than the current absolute grant values. If theabsolute grant is indicating a value above 30, the WTRU may take this asan indication to initiate transmission on the other uplink carrier. Thegrant to use on both uplink carriers may correspond to the AG splitbetween the uplink carriers. Alternatively, the AG on the new carriermay correspond to the signaled AG minus the serving grant of the currentcarrier. Alternatively, the AG index on the new carrier may correspondto the signaled AG minus 30. Alternatively, the serving grant used forthe current carrier may also be used for the new carrier.

Any of the methods described herein may be used to signal a grant on theother carrier, (for example a change of the absolute grant message suchthat absolute grant indexes may be signaled along with a new bitindicating the uplink carrier to which the grant applies).

Alternatively, an indication bit may be signaled on the E-AGCH thatindicates the WTRU to start transmission on both carriers. Uponreception of the message on the E-AGCH the WTRU may start transmissionon the other uplink carrier, either using the same serving grant as thecurrent uplink carrier or alternatively using a serving grantcorresponding to the absolute grant carried on the same E-AGCH as theindication bit.

In the above trigger conditions, the absolute grant scope may be set toa specific value (“all” or “single”).

When non-persistent grant on the carrier on which the WTRU is notcurrently transmitting is triggered, the WTRU synchronizes the newuplink carrier, if not already done. Synchronization on the new carriermay also include transmission of DPCCH preamble prior to initiation ofE-DCH transmission on the new carrier.

The WTRU may also start a non-persistent timer. The non-persistent timermay correspond to a time value or to a number of TTIs. This value may bepredetermined by the WTRU or signaled/configured to the WTRU via RRCsignaling.

The WTRU begins E-DCH transmission using the signaled non-persistentgrant using one of the methods described above. Alternatively, the WTRUmay ignore the value of the grant and use the maximum grant.Alternatively, the WTRU may ignore the value of the grant signaled anduse a maximum value signaled by the network. Alternatively, the WTRU mayus a pre-configured non-persistent grant signaled by the network via RRCsignaling or pre-determined by the WTRU.

Once the non-persistent timer expires, the serving grant associated tothe new uplink carrier takes a value of zero, and/or all HARQ processesassociated to the new uplink carriers are de-activated. The WTRU thusstops initiating new HARQ transmissions on the new carrier. Optionally,once all HARQ retransmissions on the new carrier are completed the WTRUmay implicitly de-activate the new carrier. Optionally, the WTRU maysend SI either piggy-backed at the end of the last HARQ transmissionallowed as per the non-persistent timer or by itself after the timer hasexpired. The value of the non-persistent timer may be configured by thenetwork, may be WTRU or cell-specific.

For fast group grant switching, WTRUs may be configured by the networkwith one dedicated E-RNTI and one shared E-RNTI. The network may use theshared E-RNTI to reduce the serving grant to the group of WTRUs to asignaled or configured value (e.g., null), or to restore the servinggrant to its previous value, optionally with a common offset. With thisfunctionality, the network may free the uplink resource in a cell usingthe shared E-RNTI and allocate it to a single WTRU, and later it mayresume the grant to the group of WTRUs to the previous state.

Referring now to FIG. 5, embodiments to perform power control on bothuplink carriers 520, 540 (i.e., in a dual-carrier scenario) and allocatepower and data across the uplink carriers are described hereafter. It isnoted that while specific channels are shown being carried by uplink anddownlink carriers in FIGS. 5-7 and FIG. 9, any channels may be carriedin such carriers.

In accordance with one embodiment, the transmission powers of the uplinkdedicated physical control channel (DPCCH) transmissions 525, 545 onboth uplink carriers 520, 540 are controlled by two separate transmitpower control (TPC) commands transmitted by the Node-B. One TPC commandcontrols the power of the first uplink carrier 520 and the other TPCcommand controls the power of the second uplink carrier 540. The WTRUvaries the power of the DPCCH 525, 545 on each uplink carrier 520, 540based on the corresponding TPC command

A Node-B may transmit a TPC command for an uplink carrier over an F-DPCH560, 580 on a downlink carrier 570, 590 corresponding to that uplinkcarrier 520, 540 respectively. A mapping between the uplink carrier andthe downlink carrier may be pre-defined. The WTRU typically obtains theTPC commands by listening to two channels (e.g., F-DPCH) transmittedover two different downlink carriers, but of course different channelsmay be used for transmitting such commands.

Alternatively, referring now to FIG. 6, the TPC commands for the twouplink carriers 520, 540 may be transmitted on two different channels562, 564 on the same downlink carrier 570 (either one of the downlinkcarriers 570 or 590 may be used, but 570 is shown as being used in thisembodiment). In this embodiment, the WTRU is not required to listen toboth downlink carriers 570 and 590 if there is no other activity on atleast one of the downlink carriers.

In a further alternative embodiment, shown in FIG. 7, the TPC commandsfor the two uplink carriers 520, 540 may be carried over a singlechannel 562 (e.g., F-DPCH) in a single downlink carrier 570 (again,either one of the downlink carriers 570 or 590 may be used, but 570 isshown as being used in this embodiment). FIG. 8 shows an example F-DPCHslot format in accordance with this alternative embodiment. An F-DPCHslot format includes two TPC fields per slot, where TPC1 and TCP2 eachcontain a power control command (UP or DOWN) for uplink carrier 1 anduplink carrier 2, respectively.

Referring again to FIG. 7, in another alternative embodiment, wherepower control commands for both uplink carriers are transmitted on asingle channel 562 such as the F-DPCH channel, the power controlcommands are time multiplexed. The time-multiplexing of power controlcommands may be achieved in a number of different ways. The powercontrol commands may evenly alternate between uplink carrier 1 520 anduplink carrier 2 540. For example, the uplink carrier for which thepower control command is destined may be determined as:

If (current connection frame number (CFN)+slot number) modulo 2=0, thenTPC is for uplink carrier 1;

Else, TPC is for uplink carrier 2.

For example, power control commands for uplink carrier 1 520 may becarried in radio slots #0, 2, 4, 6, 8, 10, 12, and 14; whereas powercontrol commands for uplink carrier 2 540 may be carried in radio slots#1, 3, 5, 7, 9, 11, and 13, or vice versa. Alternatively, more powercontrol commands may be allocated to uplink carrier 1 520 than uplinkcarrier 2 540. For example, power control commands for uplink carrier 1520 may be carried in radio slots #0, 1, 3, 4, 6, 7, 9, 10, 12, and 13,whereas power control commands for uplink carrier 2 540 may be carriedin radio slots #2, 5, 8, 11, and 14. This alternative may be used ifthere is a reason why providing more power control commands willincrease overall efficiency. Such a scenario may be, for example, whereuplink carrier 1 520 is carrying more physical layer channels thanuplink carrier 2 540.

Synchronization may also be defined on a per-carrier basis. The WTRU mayapply the synchronization procedure on both carriers separately. TheWTRU may be allowed to transmit on a carrier depending on thesynchronization status on that carrier. Radio link failure may bedeclared upon loss of synchronization on both carriers.

Still referring to FIG. 7, in yet another alternative of the scenariowhere power control commands for both uplink carriers are transmitted ona single channel 562 such as the F-DPCH, the transmission powers of theDPCCH transmissions on both uplink carriers may be controlled by asingle TPC command transmitted by the Node-B on, in this scenario, theF-DPCH. When the TPC command from the Node-B indicates to increase thepower, the power is (e.g., equally) increased on both uplink carriers,and when the TPC command indicates to decrease the power, the power is(e.g., equally) decreased on both uplink carriers. For example, thepower control commands may be joint-coded into a single TPC field.Example joint coding of the TPC commands is shown in Table 1 forN_(TPC)=2 and N_(TPC)=4, where N_(TPC) is the number of TPC commandbits.

TABLE 1 TPC Bit Pattern TPC Command N_(TPC) = 2 N_(TPC) = 4 N_(TPC) = 2N_(TPC) = 4 00 0000 0 0 01 0011 0 1 10 1100 1 0 11 1111 1 1

Referring now to FIG. 9, the following embodiments are in relation tothe uplink transmission of transmit power control (TPC) commands fromthe WTRU to the Node-B on the uplink DPCCH for purposes of downlinkpower control. The WTRU may transmit a TPC command on the uplink DPCCH925 of only one of the uplink carriers (in this example 920). On anotheruplink carrier (in this case 940), the WTRU may use either discontinuoustransmission (DTX) in place of transmitting the TPC bits, or a new slotformat with no TPC field. The TPC command may be derived from thequality measured on the downlink carrier 970 on which a downlink channelsuch as, for example, the F-DPCH 975 is transmitted. This approach hasan advantage of somewhat reducing the interference from the WTRU. TheWTRU may transmit the uplink DPCCH 925, 945 with only the pilot bitsused for channel estimation by the Node-B.

Alternatively, the WTRU may transmit the same TPC command on the uplinkDPCCH 925, 945 of both uplink carriers 920, 940. The TPC command may bederived from the quality measured on the downlink carrier 970 on whichthe F-DPCH 975 is transmitted. The Node-B may combine the TPC commandsignals from the two uplink DPCCHs 925, 945 to improve reliability ofthe TPC signals from the WTRU.

Alternatively, the WTRU may transmit independent TPC commands on theuplink DPCCH 925, 945 of each uplink carrier 920, 940. In this case, theTPC command sent on an uplink carrier 920, 940 may be derived based onthe signal quality measured from the corresponding downlink carrier(s)(not shown) independently of the downlink carrier on which the F-DPCH970 is transmitted. This scheme has the benefit of providing the networkwith some additional information regarding the downlink channel.

Since the uplink channels 925, 927, 945 on the two uplink carriers maynot behave the same, it is possible that the channel quality changes onone carrier 920 differently than on another carrier 940. It is alsopossible that the channel quality on one carrier 920 changes whereaschannel quality does not change on another carrier 940. In one example,channel quality degrades on one uplink carrier 920 while it improves onthe other uplink carrier 940. In this case the Node-B has differentoptions for setting the value of the TPC bits on the F-DPCH 975. TheNode-B may set the TPC bit to “up” whenever the quality from one of thecarriers 920, 940 is below a threshold, and “down” otherwise. Thisoption may result in the uplink DPCCH power being high on one of thecarriers 920, 940 making channel estimation easier for the Node-B.Alternatively, the Node-B may set the TPC bit to “down” whenever thequality from one of the carriers 920, 940 is above a threshold, and “up”otherwise. This option may result in the uplink DPCCH 925, 945 powerbeing lower than a threshold for one of the carriers 920, 940 so theNode-B may derive an acceptable channel estimate on this carrier usingthe information from the other carrier.

If the average uplink interference (noise rise) level is not the same onboth uplink carriers 920, 940, there may be a long-term and significantdiscrepancy in channel quality between the uplink carriers. The WTRU mayapply an offset to the transmission power of one of the uplink carriers(e.g., 920) compared to the other uplink carrier (e.g., 940). Thisoffset may be signaled by the network via higher layer signaling, (e.g.,RRC signaling), or the like. The network may set the offset so that theaverage signal quality from both uplink carriers 920, 940 would be thesame or similar.

The network may define different sets of reference E-DCH transportformat combination index (E-TFCI) and corresponding gain factors for thetwo uplink carriers 920, 940, so that the signal-to-interference ratio(SIR) of the E-DPDCH 927, 947 (which contains data bits) isapproximately the same on both uplink carriers 920, 940. For instance,if the DPCCH SIR of uplink carrier 1 920 is −22 dB in average while theDPCCH SIR of uplink carrier 2 940 is −19 dB in average, setting areference gain factor 3 dB lower for uplink carrier 2 (for the samereference E-TFCI) would result in approximately the same E-DPDCH SIR forboth uplink carriers 920, 940 and a given E-TFC (the reference gainfactor of uplink carrier 2 940 may actually be set slightly lower than 3dB below uplink carrier 1 920 given the better channel estimate withuplink carrier 2 940).

Synchronization may be defined on a per-carrier basis. The WTRU mayapply the synchronization procedure on both carriers separately. TheWTRU may be allowed to transmit on a carrier depending on thesynchronization status on that carrier. Radio link failure may bedeclared upon loss of synchronization on both carriers.

Still referring to FIG. 9, embodiments for E-TFC restriction andselection are described hereafter. A WTRU transmission may be restrictedby a maximum allowed transmit power. The maximum allowed transmit powerof the WTRU may be a minimum of a signaled configured value and amaximum power allowed due to WTRU design limitation. The maximum allowedtransmit power of the WTRU may be configured as a total maximum power ina given transmission time interval (TTI) for both uplink carriers 920,940, or may be carrier-specific. In the latter case, the same maximumpower value may be assigned to each uplink carrier 920, 940 or adifferent maximum power value may be assigned to each uplink carrier920, 940. This may depend on the particular configuration of the device,(e.g., the number of power amplifiers and antennas of the WTRU), and/oron network control and configuration. The total maximum transmit powerand the per-carrier maximum transmit power may be simultaneouslyconfigured.

The WTRU behavior and operation may be quite different in both cases(i.e., one total maximum transmit power or independent per-carriermaximum transmit power). Therefore, the WTRU may indicate the powercapabilities of the WTRU, (i.e., one maximum power or a maximum powerdefined per carrier), to the network so that the network knows whetherthe WTRU has a total maximum power for both uplink carriers 920, 940 ora carrier-specific maximum power for each uplink carrier 920, 940, andmay schedule operations and correctly interpret the uplink powerheadroom reported by the WTRU. If the power requirements are specifiedin the standards the WTRU may not need to signal these capabilities.

FIG. 10 is a flow diagram of an example process 1000 for E-TFC selectionand MAC-i PDU generation while utilizing two uplink carriers is shown.As mentioned above, specific terms for referring to the carriers areused interchangeably herein, but it is noted that in an HSPA+typesystem, the two carriers may be referred to as an anchor (or primary)carrier and a supplementary (or secondary) carrier and these terms willbe used for convenience in describing FIG. 10. A WTRU determines whetherthere are two (N in general, N being an integer larger than one) newtransmissions to be transmitted for the upcoming TTI (step 502). Ifthere is one new transmission for the upcoming TTI, (e.g., there are onenew transmission and one retransmission of the previous failedtransmission), the WTRU selects an uplink carrier (the carrier for thenew transmission) for E-TFC selection and performs an E-TFC selectionprocedure for the new transmission while the supported E-TFCIs for thenew transmission are determined after subtracting the power being usedby the retransmission (step 516). If there are two new transmissions tobe transmitted, the WTRU determines whether the WTRU is power limited,(i.e., sum of the total power that would be used by the WTRU in eachcarrier given the grants (scheduled and non-scheduled) and controlchannels exceed the maximum power allowed by the WTRU, optionallyincluding backoff) (step 504). If not, the process 500 proceeds to step508. If so, the WTRU performs power allocation between the uplinkcarriers (step 506). Alternatively, the WTRU may proceed to step 506 forpower allocation between the carriers without checking if the WTRU ispower limited. Once power allocation is performed the WTRU fills up thetransport blocks sequentially one carrier after the other.

The WTRU determines the MAC-d flow with the highest priority data to betransmitted, and the multiplexing list and the power offset to use basedon the HARQ profile of the selected MAC-d flow (step 508). Whendetermining the highest priority MAC-d flow the WTRU may, for everycarrier, determine the highest priority MAC-d flow configured with dataavailable amongst all MAC-d flows. In an alternate embodiment, the WTRUmay, for every carrier for which E-TFC selection or highest priorityMAC-d flow selection is being performed, determine the highest priorityMAC-d flow amongst all MAC-d flows allowed to be transmitted on thegiven carrier. The WTRU performs an uplink carrier selection procedureto select an uplink carrier among a plurality of uplink carriers to fillup with data first (step 510). It should be noted that the steps ofcarrier selection, MAC-d flow determination may not necessarily beperformed in the order described, but may be performed in any order).The WTRU selects an E-TFCI or determines the number of bits that can betransmitted on the selected carrier based on a maximum supported payload(i.e., set of supported E-TFCIs), a remaining scheduled grant payload, aremaining non-scheduled grant payload, data availability and logicalchannel priorities (step 511).

The WTRU generates a MAC-e or MAC-i PDU for E-DCH transmission via theselected carrier based on the selected E-TFC (step 512). If schedulinginformation (SI) needs to be sent for the selected carrier, the WTRU mayinitially include the SI on this carrier before including any otherdata. Once the WTRU has completed the available space on the selectedcarrier or has exceeded the data in the buffer allowed to be transmittedin the TTI, the WTRU determines whether there is another uplink carrieravailable and data is still available (step 514). If not, the process500 ends. If so, the process 500 returns to step 510 (or alternativelyto step 508) to select the E-TFCI of the next carrier.

At this point, (in step 508), the WTRU may optionally re-determine thehighest priority MAC-d flow that has data to be transmitted. There-selected highest priority MAC-d flow may be different than the onedetermined initially before filling up the previously selected carrier.If a new highest MAC-d flow is selected, the WTRU determines the poweroffset based on the HARQ profile of the newly selected MAC-d flow, andmay then determine the maximum supported payload (or set of supportedE-TFCs) and remaining scheduled grant payload according to the new poweroffset. Alternatively, the WTRU may determine the MAC-d flow priorityonly once at the beginning of the procedure (e.g., step 508) and applythe selected HARQ profile and multiplexing list to both carriers. Thisimplies that the WTRU determines the maximum supported payload (orsupported E-TFCs and remaining scheduled payload) for both carrierseither simultaneously in parallel or only at the time these values areneeded according to E-TFC selection sequence. In this case for thesecond selected carrier the WTRU may return to step 510. It should benoted that the process 500 is applicable to the case that more than twouplink carriers are utilized.

Details of the power allocation, carrier selection, and E-TFCrestriction and selection will be explained below.

The maximum supported payload refers to the maximum allowed number ofbits that may be transmitted based on the available power for any uplinkcarrier. This, as an example, may also be referred to as the maximumsupported E-TFCI. The maximum supported payload or the set of supportedor blocked E-TFCIs, for example in HSPA systems are determined as partof the E-TFC restriction procedure and may be dependent on the selectedHARQ offset. Additionally, the set of supported E-TFCI may also bedependent on the minimum set E-TFCI. Embodiments for E-TFC restrictionand determination of supported/blocked E-TFCI are described below.

Where referred to hereafter, a MAC-d flow may also refer to a logicalchannel, a group of logical channels, a data flow, a data stream, ordata service or any MAC flow, application flow, etc. All the conceptsdescribed herein are equally applicable to other data flows. For examplein HSPA system for E-DCH, each MAC-d flow is associated to a logicalchannel (e.g., there is a one-to-one mapping) and has a priority from 1to 8 associated to it.

Generally, there are scheduling mechanisms used for uplink transmissionsand data transmissions. The scheduling mechanisms may be defined by thequality of service (QoS) requirements and/or the priority of the datastreams to be transmitted. Depending of QoS and/or priority of the datastreams, some of the data streams may or may not be allowed to bemultiplexed and transmitted together in one TTI. Generally, data flowsand streams can be grouped in best effort or non real time services andguaranteed bit rate service with some strict delay requirements. Inorder to meet QoS requirements different scheduling mechanisms are used,some dynamic in nature and some less dynamic.

Generally, wireless systems, such as LTE and high speed uplink packetaccess (HSUPA), operate on a request-grant basis where WTRUs request apermission to send data, via uplink feedback, and the Node-B (eNB)scheduler and/or RNC decides when and how many WTRUs will be allowed todo so. Hereafter, this is referred to as scheduled mode transmissions.For example in HSPA systems, a request for transmission includesindication of the amount of buffered data in the WTRU and WTRU'savailable power margin (i.e., UE power headroom (UPH)). The power thatmay be used for the scheduled transmissions is controlled dynamically bythe Node-B through absolute grant and relative grant.

For some data streams with strict delay requirements and guaranteed bitrate, such as voice over IP (VoIP) or signaling radio bearers or anyother service that need to meet these requirements, the network mayensure the timely delivery of such transmissions via special schedulingmechanisms that are less dynamic in nature and allow the WTRUs totransmit data from a particular flow on at pre-scheduled time periods,resources, and up to a configured data rate. These flows in some systemssuch as HSPA for example are referred to as non-scheduled flows. Inother systems, such as LTE. they may be referred to as semi-persistentscheduling and flows. Even though the embodiments described herein aredescribed in terms of scheduled and non-scheduled data, it should beunderstood that they are equally applicable to other systems that usesimilar scheduling procedure and distinctions between data flows.

Dynamic scheduling, where control channels are used to allocate theresources for certain transmissions and for the possibleretransmissions, gives full flexibility for optimizing resourceallocation. However, it requires control channel capacity. In order toavoid control channel limitation problem, semi-persistent scheduling(SPS) may be used in systems such as LTE and non-scheduled transmissionin systems such as UMTS. Flows that use dynamic scheduling or thedynamic grant-based mechanism (e.g., via physical channel controlsignaling) will be referred to as scheduled transmissions. Data streamsthat use a more semi-static and periodic allocation of resources will bereferred to as non-scheduled transmissions.

For example, in HSPA, each MAC-d flow is configured to use eitherscheduled or non-scheduled modes of transmissions, and the WTRU adjuststhe data rate for scheduled and non-scheduled flows independently. Themaximum data rate of each non-scheduled flow is configured by higherlayers, and typically not changed frequently.

In the E-TFC selection procedure, the WTRU may also determine theremaining non-scheduled grant payload for each MAC-d flow with anon-scheduled grant, which refers to and correspond to the number ofbits allowed to be transmitted according to the configured non-scheduledgrant for the given MAC-d flow.

The remaining scheduled grant payload in the procedure above refers tothe highest payload that could be transmitted according to the networkallocated resources after power allocation for other channels. Forexample, a network allocated resource refers to the serving grant andselected power offset of the corresponding carrier for HSPA systems. Thevalue of the serving grant used for calculating the remaining scheduledgrant payloads for the uplink carriers may be based on the value of theactual serving grant allocated for the uplink carriers. Alternatively,as the remaining scheduled grant payload for the primary carrier and/orthe secondary carrier may be based on the scaled or fictitious orvirtual grant after power allocation is performed, the WTRU may use the“virtual” or “fictitious” or scaled serving grant to determine theremaining scheduled grant payload. The three terms may be usedinterchangeably and refer to the power allocation or power split forscheduled transmissions for each carrier. The scaling of the grants isdescribed as part of the power allocation schemes below. Alternatively,if the WTRU is sharing one serving grant for both uplink carriers,(i.e., one serving grant is given for both uplink carriers), the WTRUmay use half the serving grant for each uplink carrier. Alternatively,the WTRU may assume that all serving grant is being allocated to oneuplink carrier when performing this calculation.

The non-scheduled grant may be carrier specific, (e.g., the configurednon-scheduled grant value is assigned and configured for only onecarrier, the carrier for which non-scheduled transmission is allowed).The carrier in which non-scheduled transmission is configured/allowedmay be predetermined, (e.g., the non-scheduled transmission may beallowed only on the primary carrier or alternatively on the secondarycarrier). Alternatively, it may be configured by the networkdynamically. The value of non-scheduled grant may be carrierindependent, in which case a total number is determined for bothcarriers.

Data flows may be configured to be carrier specific (e.g., networkconfigures a flow and an associated carrier over which this flow may betransmitted). If data flows are carrier specific the WTRU may performthe E-TFC selection procedure independently for each carrier. Thenetwork may provide a non-scheduled grant based on a HARQ process thatbelongs to a carrier, or provide a non-scheduled grant that isapplicable to a TTI, and the WTRU chooses a carrier.

Embodiments for selecting an uplink carrier for initial E-TFC selectionare disclosed hereafter. The embodiments for carrier selection describedbelow may be performed individually or in combination with any otherembodiments disclosed herein. The procedures affecting the choice of thenumber of bits to be transmitted in each uplink carrier and the power touse in each uplink carrier, and the like are all dependent on whichuplink carrier the WTRU selects and treats first.

In accordance with one embodiment, a WTRU may give priority to, andtreat first, the anchor carrier. This may be desirable if non-scheduledtransmissions are allowed on the anchor carrier. Alternatively, thesecondary carrier may be given a priority and selected first.

Alternatively, the WTRU may determine the highest priority carrier tominimize inter-cell interference, maximize WTRU battery life, and/orprovide the most efficient energy per bit transmission. Morespecifically, the WTRU may choose the uplink carrier that has thelargest calculated carrier power headroom. The WTRU may base thisdetermination on the current power headroom, (e.g., UE power headroom(UPH)) measurement for each carrier (UPH indicates the ratio of themaximum WTRU transmission power and the corresponding DPCCH code power)or on the results of the E-TFC restriction procedure, (e.g., normalizedremaining power margin (NRPM) calculation for each carrier, or remainingpower), which equivalently translates to the carrier with the lowestDPCCH power (P_(DPCCH)). For instance, the uplink carrier selection maybe made in terms of the number of bits, (e.g., a priority may be givento the carrier which provides a greater “maximum supported payload”between the anchor carrier and the supplementary carrier). The maximumsupported payload is the payload determined based on the remaining power(e.g., NRPM or other value disclosed below) of the WTRU.

Alternatively, the WTRU may give a priority to the uplink carrier whichprovides the WTRU with the largest available grant, which allows theWTRU to send the highest amount of data and possibly create the leastnumber of PDUs and thus increase efficiency and reduce overhead. TheWTRU may select a carrier based on the maximum value between the servinggrant for the anchor carrier (SGa) and serving grant for thesupplementary carrier (SGs).

Alternatively, the WTRU may provide a priority to the carrier thatprovides the greater “remaining scheduled grant payload” between theanchor carrier and the supplementary carrier. The remaining scheduledgrant payload is the available payload determined based on thescheduling grant from the network and remaining after processing of theDCH and HS-DPCCH.

Alternatively, the WTRU may optimize between maximum power and maximumgrant. More specifically, the WTRU may select a carrier that allows thehighest number of bits to be transmitted. The WTRU determines the numberof bits that may be transmitted for anchor carrier and supplementarycarrier limited by both power and grant, (i.e., “available payload” forthe anchor carrier and “available payload” for the supplementarycarrier), and may select the carrier that provides the highest availablepayload. The available payload may be determined as a minimum betweenthe remaining scheduled grant payload and the maximum supported payload.

Optionally, the sum of “remaining non-scheduled payload” for each MAC-dflow that may be multiplexed (or all non-scheduled MAC-d flows that mayhave data available) may also be taken into account when calculating theavailable payload. More specifically, the available payload may bedetermined as a minimum of (remaining scheduled grant payload+SUM(remaining non-scheduled payloads for all allowed non-scheduled flows))and the maximum supported payload. If non-scheduled flows are allowed inone carrier only, (e.g., in the anchor carrier only), the availablepayload for the anchor carrier is considered.

If the non-scheduled grants are provided on a per carrier basis or ifthe non-scheduled transmissions are allowed on one carrier, the WTRU maygive priority to the carrier that contains the highest prioritynon-scheduled MAC-d flow to be transmitted in that TTI or allows anon-scheduled MAC-d flow. For instance, if the non-scheduledtransmissions are allowed on the primary carrier only and for the givenHARQ process the WTRU is configured with non-scheduled data and data isavailable, the WTRU may give priority to the primary carrier (i.e., fillthe primary carrier first). If in a given TTI the highest priority MAC-dflow does not correspond to a non-scheduled flow, but a non-scheduledflow is allowed to be multiplexed with the selected highest priorityMAC-d flow, the WTRU may still give priority to the carrier which allowsnon-scheduled transmissions. Therefore, if any non-scheduled flows areallowed to be transmitted in a current TTI and non-scheduled data isavailable, the WTRU may first fill up the carrier which allowstransmission of the non-scheduled flows. The WTRU fills up the selectedcarrier with non-scheduled and scheduled data up to the available powerand/or grant according to the configured logical channel priority. Theremaining carrier(s) is then filled up if data, power and grant areavailable for that carrier.

Alternatively, the WTRU may base its decision to select a carrier on oneor a combination of CPICH measurement and HARQ error rates on eachcarrier, etc.

Example embodiments for E-TFC selection for independent maximum powerlimitation are explained hereafter. The WTRU may have a differenttransmission powers and maximum allowed power for each carrier, whichmay depend on the particular device configuration or design. Thisdepends on implementation design, (e.g., a WTRU may be designed with twodifferent power amplifiers and two different antennas), and/or onnetwork control and configuration. It is also applicable if the WTRUpre-allocates the power between the carriers, or allocates the power inparallel, as described below. In these situations, the maximum power oravailable power that may be used by each carrier corresponds to theallocated power per carrier. The embodiments are also applicable to thecase where power is shared between the carriers but the power isallocated or scaled between the carriers prior to filling up thecarriers.

Where the powers are pre-allocated or the maximum amount of power isindependent on each carrier, the MAC PDUs may have to be filled upsequentially due to the fact that the delivery order of RLC PDUs has tobe maintained in order to allow proper operation of higher layers.Additionally, the WTRU may be buffer limited in which case enough datato transmit over one carrier may be available.

In this situation, the WTRU may initially choose the highest prioritycarrier P1 based on one of the embodiments described above. Forinstance, the WTRU may select the carrier with the higher powerheadroom, equivalently the carrier with the lower DPCCH power to befilled up with data first or the primary or secondary carrier may befilled up first. This allows, even a buffer limited WTRU to transmitmost of its data, or its highest priority data, over the carrier withthe best channel quality or over the carrier that allows transmission ofthe highest priority data, such as non-scheduled transmissions.

According to the highest priority MAC-d flow, associated HARQ profileand multiplexing list, the WTRU then fills up the available space on thetransport block of carrier p1 (i.e., creates MAC-e or MAC-i to be senton carrier p1), according to the “Maximum Supported Payload p1”,“Remaining Scheduled Grant Payload p1”, and remaining non-scheduledgrant payload, if allowed and configured in the selected carrier, P1. Aspreviously mentioned, this corresponds to the number of bits that may betransmitted according to the allowed power, allowed scheduled grant, andallowed non-serving grant, respectively. In this situation, allowedpower and allowed grant may correspond to scaled values of the powerand/or grant of each carrier or the configured powers or grants. Thismay be done if the power or grant is proportionally split between thetwo carriers or allocated in parallel. If SI needs to be sent, the WTRUmay send it in carrier p1, or alternatively send it in the carrier inwhich the SI is configured to be transmitted.

Once the WTRU has completed the available space on carrier p1, it thenfills up next carrier. At this point the WTRU may re-determine thehighest priority MAC-d flow that has data to be transmitted and isallowed in the carrier being treated. At this point the highest priorityMAC-d flow may be different than the one determined initially, prior tocarrier p1 being filled up.

When determining the highest priority MAC-d flow the WTRU may, for everycarrier, determine the highest priority MAC-d flow configured with dataavailable amongst all MAC-d flows. In an alternate embodiment, the WTRUmay, for every carrier for which E-TFC selection or highest priorityMAC-d flow selection is being performed, determine the highest priorityMAC-d flow amongst all MAC-d flows allowed to be transmitted on thegiven carrier.

If the carrier for which E-TFC selection is being performed does notallow a certain type of MAC-d flow, when determining the highestpriority MAC-d flow the WTRU may not consider the MAC-d flows that arenot allowed for transmission on the given carrier. For instance, if theWTRU is performing E-TFC selection for the second carrier, it may notinclude non-scheduled MAC-d flows in the selection of highest priorityMAC-d flow. So if a non-scheduled MAC-d flow has data available and hasthe highest configured MAC-d priority the WTRU may not use this MAC-dflow as its highest priority MAC-d flow and may not use the HARQprofile, power offset and HARQ retransmission, and multiplexing list forthe TTI for the carrier. For specific example, for HSPA dual carrier ULwhen treating the second carrier the WTRU may determine the highestpriority MAC-d flow amongst all scheduled MAC-d flows.

Once the highest MAC-d flow is determined, the WTRU determines the newallowed MAC-d flows that may be multiplexed in this TTI, and the poweroffset based on the HARQ profile of the selected MAC-d flow to be usedfor the new carrier. The WTRU may then determine the Maximum SupportedPayload and Remaining Scheduled Grant Payload according to the new poweroffset and fill up the carrier with data if available accordingly.

Alternatively, the WTRU may determine the Maximum Supported Payload andRemaining Scheduled payload for both carriers at the beginning of theE-TFC selection procedure or prior to filling up the carrier, whichimplies that the WTRU can use the same power offset for both carriersregardless of whether data from that first highest selected MAC-d flowis being transmitted on both carriers. In this case, the multiplexinglist will remain the same on both carriers and may be a limiting factorwhen not enough data is available from those logical channels, but theWTRU has more power and grant available for transmission of otherlogical channels.

Once carrier p1 (which may be determined as above and filled upsequentially) is filled up with data, the WTRU immediately moves to theother carrier and continues to fill it up with data.

Alternatively, the carriers may be filled up in parallel, which impliesthat the data from all the allowed logical channels is split between thetwo carriers. In order to avoid out-of-order delivery, the data or theRLC buffer has to be split. For instance, if 10 RLC PDUs with SN 0 to 9are available, RLC PDUs 0 to 4 are sent to carrier one and 5 to 9 aresent to carrier two. The WTRU then moves to the next logical channel ifspace still remains and the buffer is again split in the same way.

Alternatively, the E-TFC and carrier filling may be performed inparallel, but each carrier takes data from different logical channels.This implies that the WTRU selects the two highest priority MAC-d flows,determines the HARQ profile for each and the multiplexing list for eachand maps them to the two individual carriers. This will allow the WTRUto fill up and perform E-TFC in parallel without risking out-of-orderRLC delivery. However, this may result in situations where data from thehighest logical channel is still available but the WTRU may no longersend them, since the carrier is full.

In another embodiment, data flows may be carrier specific. In this casethe WTRU may perform the E-TFC selection procedure independently foreach carrier.

Example embodiments for E-TFC selection for total combined maximum powerlimitation are described hereafter. Some of the aspects of theseembodiments may also be applicable as described above if the powerbetween the two carriers is allocated in parallel or some form ofdynamic power allocation is performed.

In a sequential approach, when the WTRU maximum power is shared amongstboth carriers, the WTRU may initially select the highest prioritycarrier (P1) using one of the embodiments described above. E-TFCrestriction and selection may still be performed sequentially, whereinthe available power and grant used are equivalent to the allocated orscaled power or grant.

Once the WTRU has selected the highest priority carrier, the WTRUperforms the E-TFC selection and restriction procedure, where thehighest priority MAC-d flow is selected and the power offset, theMaximum Supported payload p1 is determined, the Scheduled AvailablePayload is selected according to the serving grant of carrier P1 and thenon-scheduled available payload is selected. If SI needs to betransmitted, it may be treated with the first selected carrier oralternatively it may be treated on the carrier in which it is allowed tobe transmitted. In this case, the WTRU may perform a sequential E-TFCrestriction procedure as described above, where the WTRU assumes all thepower is available to be used by carrier P1 and assuming that no data isbeing transmitted on the secondary carrier. The WTRU creates a MAC-e orMAC-i PDU to be transmitted on this carrier according to the E-TFCselection. Alternatively, if the SI is sent in one carrier only (i.e.,the anchor carrier only), then the E-TFC selection takes it into accountwhen performing E-TFC for the carrier in which the SI is being sent.

The maximum supported payload, (i.e., E-TFC restriction), for theselected carrier may be determined, for example, according to the NRPMcalculation. In the case where the WTRU has a retransmission in carrierx, then no E-TFC selection is performed for carrier x. The WTRU performsE-TFC selection and creates a MAC-i or MAC-e PDU for the carrier y, theremaining carrier.

The WTRU then has to create a MAC-e or MAC-i PDU for the remainingcarrier.

At this point the WTRU may re-determine (or determine for the first timeif a retransmission is ongoing on carrier x) the highest priority MAC-dflow that has data to be transmitted and the power offset based on theHARQ profile of the selected MAC-d flow and the MAC-d flow multiplexinglist. Alternatively, the WTRU uses the same power offset determinedinitially in the procedure.

The WTRU then performs the E-TFC restriction procedure for this secondcarrier. The WTRU may take into account the power that will be used fromthe first carrier and the remaining available power is used whencalculating the maximum supported payload or when determining the set ofsupported E-TFCIs. Alternatively, the WTRU may subtract a “backoffpower” (i.e., the particular power losses experienced when the WTRUtransmits on two carriers in the same TTI), prior to performing theE-TFC restriction on the second carrier, (i.e., the second selectedcarrier), when two new transmissions take place or when one newtransmission is taking place due to a HARQ retransmission in the othercarrier.

In these embodiments described herein, the WTRU may be configured to notto transmit a DPCCH when it is determined that data does not need to besent. The WTRU may also be configured to not transmit any data on asecond carrier if it does not have enough power where the maximum poweris allocated per carrier. For instance, if one of the carriers does nothave enough power, the WTRU may use one carrier to transmit (the onethat has the highest UPH or highest NRPM), instead of using the minimumset E-TFCI, or alternatively, the WTRU may not transmit in one of thecarriers if both do not have enough power. The WTRU may use the minimumset on one of the carriers and may not transmit on the second.

The MAC-i or MAC-e PDU is then filled up according to the determinedmaximum supported payload, the scheduled available payload (according tothe serving grant of this carrier), and the non-scheduled availablepayload, if applicable.

In another embodiment, the WTRU may select the E-TFC on each carrier insuch a way that the transmission power (over all UL channels, i.e.,DPCCH, E-DPCCH, HS-DPCCH, E-DPDCH) on each carrier is the same or thedifference between the two is less than a pre-configured maximum value.This may be achieved, for instance, by calculating for a giventransmission power level which E-TFCs may be transmitted on each carriergiven the transmission power of the DPCCH and other channels on eachcarrier. For instance, assuming that the DPCCH power levels are 7 dBmand 10 dBm on, say, carriers 1 and 2 respectively, and that the powerlevels of the HS-DPCCH and E-DPCCH are each −3 dB below that of theDPCCH, if the transmission power level on each carrier is 18 dBm, thepower headrooms on each carrier are 8 dB and 5 dB respectively, and thecorresponding E-TFC sizes may be 600 bits and 300 bits. Thus the WTRUmay transmit with equal power (of 18 dBm) on both carriers by selectingan E-TFC of 600 bits on the carrier 1 and an E-TFC of 300 bits oncarrier 2.

This principle may be applied in different cases. If the WTRUtransmission is limited by the maximum UL power, the WTRU may select theE-TFC on each carrier by splitting the maximum UL power equally betweenthe two carriers (thus the UL power available to each carrier would be 3dB below the maximum) and determining the maximum supported E-TFC oneach carrier using the method disclosed above. If the WTRU transmissionis limited by the amount of data in the WTRU buffer, the WTRU may seekthe transmission power level of both carriers such that the amount ofdata that may be transmitted with the resulting E-TFCs on each carriercorresponds to the amount of data in the buffer.

In another embodiment, the WTRU may select the E-TFC on each carrier insuch a way that the interference load incurred on each carrier is sameor approximately the same. The interference load incurred on a carriermay, for instance, be estimated as the power ratio between the E-DPDCHpower and the DPCCH power, which corresponds to the power ratio used forscheduling. Thus, provided that the scheduling grant and the powerheadroom is sufficient on both carriers, the WTRU selects the E-TFC oneach carrier by determining how many bytes may be transmitted from theWTRU buffer, based on grant and by determining the needed E-TFC size oneach carrier by dividing this number of bytes by 2 and applying theappropriate MAC headers.

This method would result equal power ratios on each carrier providedthat mapping between reference power ratios and reference E-TFCs is thesame between the carriers, and provided that all the data belong tological channels that have the same HARQ offset. In case where the databelongs to logical channels that do not all have the same HARQ offset,the WTRU has to find which sharing of bytes that result in the samepower ratio for both E-TFCs.

Embodiments for dual-carrier power back-off and maximum power reductionfor multicarrier operations are disclosed hereafter. To relieve the WTRUpower amplifier design and power consumption, the WTRU is typicallyallowed a certain maximum power reduction (MPR). This power reductionmargin allows a WTRU implementation to reduce the maximum transmissionpower (this is also referred to as power back-off) to avoid causingunintended adjacent carrier interference due to power amplifiernon-linearity.

In accordance with one embodiment, a power back-off may be applied whentransmitting on two uplink carriers rather than one. The WTRU determinesthe amount of data to be transmitted on both carriers according to anyof the embodiments described herein, and may apply a power back-off(i.e., reduction in total transmission power or per-carrier transmissionpower) if data is to be sent on two carriers. The application of a powerback-off would then result in the use of a smaller E-TFCI on eachcarrier. The WTRU may determine whether more data may be sent using asingle carrier without power back-off or using two carriers with powerback-off, and select the option allowing for transmission of most totalnumber of bits.

The scheduling information (SI) may be modified such that it providesthe UL power headroom measurement for each carrier individually. Morespecifically, the format of the SI may be expanded to include UPH forthe supplementary carrier, as shown in FIG. 11, where UPH1 and UPH2,correspond to the ratio of the maximum WTRU transmission power and thecorresponding anchor and supplementary DPCCH code power, respectively.

Alternatively, the WTRU may report one UPH measurement, and the Node-Bmay infer the UPH of the other carrier based on the noise risedifference between the carriers.

Alternatively, a single UPH may be calculated and reported as:

UPH=P _(max,tx)/(P _(DPCCH1) +P _(DPCCH2)),  Equation (1)

where P_(max,tx) is the total maximum output power that may betransmitted by the WTRU and P_(DPCCH1) and P_(DPCCH2) represent thetransmitted code power on DPCCH of carrier 1 and carrier 2,respectively. In the case where per-carrier maximum transmission powersare configured, then P_(max,tx) represents the sum of the per-carriermaximum transmission powers.

Alternatively, the scheduling information format remains unchanged, butthe WTRU may report the SI individually in each carrier. For instance,if the SI is sent over the anchor carrier it reports the UPH of theanchor carrier, and if it sent over the supplementary carrier it reportsthe UPH of the supplementary carrier.

Although features and elements are described above in particularcombinations, each feature or element can be used alone without theother features and elements or in various combinations with or withoutother features and elements. The methods or flow charts provided hereinmay be implemented in a computer program, software, or firmwareincorporated in a computer-readable storage medium for execution by ageneral purpose computer or a processor. Examples of computer-readablestorage mediums include a read only memory (ROM), a random access memory(RAM), a register, cache memory, semiconductor memory devices, magneticmedia such as internal hard disks and removable disks, magneto-opticalmedia, and optical media such as CD-ROM disks, and digital versatiledisks (DVDs).

Suitable processors include, by way of example, a general purposeprocessor, a special purpose processor, a conventional processor, adigital signal processor (DSP), a plurality of microprocessors, one ormore microprocessors in association with a DSP core, a controller, amicrocontroller, Application Specific Integrated Circuits (ASICs), FieldProgrammable Gate Arrays (FPGAs) circuits, any other type of integratedcircuit (IC), and/or a state machine.

A processor in association with software may be used to implement aradio frequency transceiver for use in a wireless transmit receive unit(WTRU), user equipment (UE), terminal, base station, radio networkcontroller (RNC), or any host computer. The WTRU may be used inconjunction with modules, implemented in hardware and/or software, suchas a camera, a video camera module, a videophone, a speakerphone, avibration device, a speaker, a microphone, a television transceiver, ahands free headset, a keyboard, a Bluetooth® module, a frequencymodulated (FM) radio unit, a liquid crystal display (LCD) display unit,an organic light-emitting diode (OLED) display unit, a digital musicplayer, a media player, a video game player module, an Internet browser,and/or any wireless local area network (WLAN) or Ultra Wide Band (UWB)module.

1-18. (canceled)
 19. A method implemented by a wireless transmit receiveunit (WTRU) capable of communicating using long term evolution(LTE)-Advanced wireless communications, the method comprising: the WTRUreceiving a message from a network assigning a primary downlink carrier;the WTRU determining a primary uplink carrier associated with theprimary downlink carrier; the WTRU determining one or more secondarydownlink carriers and one or more secondary uplink carriers; and theWTRU sending first feedback information associated with the primarydownlink carrier and second feedback information associated with atleast one of the one or more secondary downlink carriers on an uplinkcontrol channel of the primary uplink carrier.
 20. The method of claim19, wherein the WTRU does not utilize a control channel for sendingfeedback information on the one or more secondary uplink carriers. 21.The method of claim 19, wherein the first and second feedbackinformation correspond to acknowledgement (ACK)/negative ACK (HACK) HARQinformation.
 22. The method of claim 19, wherein each of the one or moredownlink carriers includes a downlink control channel that is used bythe WTRU for receiving scheduling information for one of the one or moresecondary uplink carriers.
 23. The method of claim 19, wherein the eachof the first and second feedback information comprises at least one ofchannel quality information or precoding information.
 24. The method ofclaim 19, further comprising the WTRU receiving a grant message via adownlink carrier control channel of one of the primary downlink carrieror one of the one or more secondary downlink carriers, wherein the grantmessage includes a field that indicates which uplink carrier is to beused for transmitting in accordance with the grant message.
 25. Themethod of claim 19, wherein a number of the one or more secondarydownlink carriers exceeds the number of the one or more secondary uplinkcarriers.
 26. The method of claim 19, wherein semi-persistent schedulingis allowed on the primary downlink carrier and primary uplink carrierbut not allowed on the one or more secondary downlink carriers andsecondary uplink carriers.
 27. The method of claim 19, furthercomprising the WTRU sending first uplink data via a first uplink datachannel on the primary uplink carrier and second uplink data via asecond uplink data channel of the secondary uplink carrier.
 28. Awireless transmit/receive unit (WTRU) comprising: a processor configuredto: receive a message from a network that assigns a primary downlinkcarrier; determine a primary uplink carrier associated with the primarydownlink carrier; determine one or more secondary downlink carriers andone or more secondary uplink carriers; and send first feedbackinformation associated with the primary downlink carrier and secondfeedback information associated with at least one of the one or moresecondary downlink carriers on an uplink control channel of the primaryuplink carrier.
 29. The WTRU of claim 28, wherein the WTRU does notutilize a control channel to send feedback information on the one ormore secondary uplink carriers.
 30. The WTRU of claim 28, wherein thefirst and second feedback information correspond to acknowledgement(ACK)/negative ACK (HACK) HARQ information.
 31. The WTRU of claim 28,wherein each of the one or more downlink carriers includes a downlinkcontrol channel that is used by the WTRU to receive schedulinginformation for one of the one or more secondary uplink carriers. 32.The WTRU of claim 28, wherein the each of the first and second feedbackinformation comprises at least one of channel quality information orprecoding information.
 33. The WTRU of claim 28, wherein the processoris further configured to receive a grant message via a downlink carriercontrol channel of one of the primary downlink carrier or one of the oneor more secondary downlink carriers, wherein the grant message includesa field that indicates which uplink carrier is to be used to transmit inaccordance with the grant message.
 34. The WTRU of claim 28, wherein anumber of the one or more secondary downlink carriers exceeds the numberof the one or more secondary uplink carriers.
 35. The WTRU of claim 28,wherein semi-persistent scheduling is allowed on the primary downlinkcarrier and primary uplink carrier but not allowed on the one or moresecondary downlink carriers and secondary uplink carriers.
 36. The WTRUof claim 28, wherein the processor is further configured to send firstuplink data via a first uplink data channel on the primary uplinkcarrier and second uplink data via a second uplink data channel of thesecondary uplink carrier.